Developments in lightwave technology continue today at a rapid pace. Such advances have improved the system performance and reduced the cost of fiber optic cables and associated optoelectronic equipment, which carry information over hair-thin strands of glass instead of conventional metallic media. Consequently, because of these considerations and additional performance advantages as well, fiber optic cable has supplanted copper wire as the preferred transmission medium in many telecommunications applications.
Initially, fiber optic cable was installed only in long-distance, intercity networks and interoffice trunks. Today, however, such cable is being placed in the local loop feeder network. Future applications will extend fiber optic cable for distribution to the customer premises itself. In fact, a proliferation of new information services is now available, or is being proposed for the office and home by local tel.-e phone companies and cable TV companies, to take advantage of the high communication capacity that fiber optic cable offers. Such interactive services include, for example, local area networks (LANs), educational and entertainment video, energy management, alarm monitoring, home banking, and videotext.
Relief of congested transmission facilities and demand for the above-identified information services will require placement of new fiber optic facilities, especially aerial cable installations in less-populated areas, where such facilities are geographically dispersed, where terrain or construction conditions so dictate, or where other economic reasons dictate.
Notwithstanding the advantages of fiber optic cable and increased demand, there are still drawbacks to universally using fiber optic cable instead of conventional metallic media. First, fiber optic cable is more fragile than copper wire or coaxial cable. In addition, fiber optic cable is more sensitive to pulling, bending and crushing forces. Accordingly, fiber optic cable demands more stringent installation and maintenance techniques than those media.
The most one important fiber optic cable parameter is its bending radius. When a fiber optic cable is being installed, and when it is finally in place, the cable must not be bent less than the minimum cable bending radius specified by the manufacturer. If the cable is otherwise mishandled, portions of the cable have to be replaced because broken, crushed or kinked cables result in degraded transmission performance.
The time and expense (and inconvenience to customers as well) associated with replacing or relocating aerially-installed fiber optic cable is substantial. This is due to high manpower requirements and the use of expensive equipment needed to install, test and maintain such transmission facilities. Those skilled in the art have not yet addressed the need to reduce the costs and inefficiencies associated with such activity after initial installation of fiber optic cable is completed. Known patents in this field have not been directed to these concerns. For example U.S. Pat. No. 4,856,867 to Gaylin (1989) discloses a flexible sheath support assembly and a method of supporting a fiber optic cable from a messenger strand using that sheath assembly.
U.S. Pat. No. 4,795,856 to Farmer (1989) discloses another apparatus for supporting fiber optic cable on a utility pole using bifurcated arms and helical ties.
Finally, U.S. Pat. No. 4,832,442 to Pappas (1989) discloses another method and apparatus for the aerial installation of long-haul cable facilties. None of these prior art inventions teaches a device or a method that facilitates the repair or relocation of aerially-installed fiber optic cable that needs servicing after installation.
One novel way of minimizing, or even obviating, downtime when undertaking such activity is by providing, during the initial installation of the fiber optic cable, a section of cable slack. When repair or relocation work becomes necessary, cable slack is then readily available at the given location, and long spans of installed cable need not be affected. Thus, the present invention provides a unique solution to the problems discussed above.
It is therefore an object of the present invention to provide a novel apparatus and method that will inexpensively support and maintain slack of a fiber optic cable in an aerial installation.
Additional objects and advantages of the invention will be set forth in the description which follows.